Forum for Science, Industry and Business

Globetrotting pollutants turn up on Toronto street

20.10.2004

Forest fire particles come to town

Researchers at the University of Toronto have detected migratory pollutants from a forest fire in Quebec and even particles from a sandstorm in the Sahara in Toronto air, findings that could someday give regulatory agencies an idea of who is contributing to the pollutants found in urban air.

"Its a bit of detective work," says Greg Evans, a professor in the Department of Chemical Engineering and Applied Chemistry. "We happened to know when that forest fire was happening in Quebec and we realized that this mixture of different particles that we found in downtown Toronto is a signature for a forest fire." With the dust particles from the Sahara, the researchers recognized sand-like particles and were ultimately able to track their trajectory from the desert, across the Atlantic Ocean to Mexico, then north through the United States to Toronto.

The researchers used a device known as a laser ablation mass spectrometer (LAMS), which pulls in air from College Street and accelerates the pollutants to close to the speed of a bullet. As a particle passes by two lasers, sensors calculate its exact speed and tell the LAMS when to fire a third, high-powered laser that vaporizes a portion of the particle, sending fragments hurtling along a "flight tube". Lighter molecules take less time to travel down the flight tube, giving the researchers the particles chemical signature. Evans says that once they build up a library of particles, this research could make it possible to identify pollutants without any knowledge of their origin.

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...